我应该如何将JPA实体序列化为JSON格式

import com.fasterxml.jackson.databind.ObjectMapper;

@RestController
@RequestMapping("/api")
public class MyController {

    @Autowired
    private EntityManager entityManager;

    @GetMapping("/entity/{id}")
    public ResponseEntity<String> getEntityJson(@PathVariable Long id) {
        // 从数据库中获取实体对象
        MyEntity entity = entityManager.find(MyEntity.class, id);

        // 将实体对象转换为JSON格式
        ObjectMapper objectMapper = new ObjectMapper();
        String json = objectMapper.writeValueAsString(entity);

        // 返回包含JSON数据的响应对象
        return ResponseEntity.ok(json);
    }
}